1. Reminder: Please use our affiliate links for holiday shopping!

Olympus mc-20 2x teleconverter?

Discussion in 'Micro 4/3 News and Rumors' started by Giiba, Oct 9, 2016.

  1. Giiba

    Giiba Something to someone somewhere

    273
    Aug 19, 2016
    Burnaby, BC
  2. Ross the fiddler

    Ross the fiddler Mu-43 Hall of Famer

    It could be interesting, but would need to only be used with the best optical lenses, like the EC20 does. It struggles with the 50-200 f2.8-3.5.
     
  3. alex g

    alex g Mu-43 Top Veteran

    542
    Mar 30, 2016
    New York / Bath
    It's certainly interesting, but it's hard to know what to think about it. The performance of the MC-14 is generally considered to be disappointing when used with either of its intended partners (the 40-150 and 300 pro lenses), particularly in comparison to its four-thirds equivalent, the EC-14, which is typically more successful in preserving the IQ of the main lens. It's unclear if the reason is due to the design of the MC-14 in particular, or an inherent constraint of the u43 format, since there are no alternative u43 teleconverters to compare it with.

    It would be nice to think that, since releasing the MC-14, Olympus have come up with a better approach, which they plan to use in a future MC-20 — let's hope they have. But if my understanding of the physics involved is correct, the u43 format presents a relatively narrow performance window lying between the softening effects of a wide aperture at one end and diffraction-limiting at the other. Lenstip.com cites the case of the 300mm f/4, which exhibits peak resolution at f/5.6, with diffraction beginning to affect performance as early as f/8. With the MC-14 attached, the lens is relatively soft at an effective aperture of f/5.6, decently sharp at f/8, and starts to tail off from there onwards due to the diffraction limitations of the entire system. In other words, f/8 is both the smallest and the largest effective aperture from which to expect to see impressive IQ. A hypothetical 2X teleconverter would reduce the effective aperture a further stop, meaning that the combined optic would be already feeling the effects of diffraction as soon as the main lens had reached its maximum resolution.

    On the other hand, the 40-150 Pro is a stop faster than the 300, which provides just enough speed to absorb the 2 EV loss of a 2X teleconverter before the onset of diffraction effects. E.g. at f/2.8 (f/5.6 effective), the 40-150 + MC-20 combination would be soft thanks to the TC magnifying the 40-150's inherent wide-open aberrations, and f/4 (f/8 effective) would be the most likely aperture to show decent IQ.

    So it might work for the 40-150 from the point of view of sharpness, if my naive take on the theory is valid. Of course there is more to IQ than just sharpness, and it must be said that the MC-14 doesn't do the 40-150 any favours when it comes to its bokeh qualities, specifically in situations where the subject is close to a busy background. It seems that, to an extent, the 40-150's exceptional sharpness comes at the price of over-corrected spherical aberrations, which are characterised by dense, bright edges to the out-of-focus specular circles and, consequently, a subjectively nervous bokeh. In my experience, the MC-14 further emphasizes this effect. But it's probably more of an issue for wildlife photographers, since their subjects often choose to lurk close to their nervous-bokeh-provoking natural cover. :hiding:
     
  4. Rasmus

    Rasmus Mu-43 Top Veteran

    657
    Nov 16, 2013
    Stockholm, Sweden.
    Just my thought. I'm very sceptical about any m4/3 lens that is slower than f/5.6 wide open. My 300/2.8 is very sharp with the EC-14 and acceptably sharp with the EC-20, while the 150/2 is great with both converters. I also have an old Nikon 500/4 and a Nikon TC-300 2X converter. That combo is supposed to be fantastic, but on m4/3 it isn't as it's f/8 wide open (add to that the impossible stability requirements at 1000 mm). Combined with the speed booster it becomes roughly 700/5.6 and that is actually somewhat useful.
     
  5. Hypilein

    Hypilein Mu-43 Veteran

    286
    Mar 18, 2015
    I could imagine getting something like this for my Panasonic 35-100 if it was compatible as it would probably be preferable to buying another lens. I would accept that f5.6 and sharpness would possibly not be ideal, but they sure beat cropping.
     
    • Agree Agree x 1
    • Informative Informative x 1
  6. ijm5012

    ijm5012 Mu-43 Hall of Famer

    Oct 2, 2013
    Pittsburgh, PA
    Ian
    I just never understood why the MC-14 had to have the element extend up in to the backside of the lens, compared to the EC-14 where the optics were housed entirely within the teleconverter. If the MC-14 had adopted a design like the EC-14, in theory it would have worked with any m43 lens. It'll be interesting to see how the MC-20 is designed.

    I too question what lenses it could realistically be used with, given the loss of 2 stops. The 40-150 would be f/5.6, which would be acceptable. But the 12-100 would be f/8 wide open, as would the 300mm pro. That leaves the user with almost no headroom to stop the lens down before starting to soften the resulting image.
     
  7. Giiba

    Giiba Something to someone somewhere

    273
    Aug 19, 2016
    Burnaby, BC
    I know the pixel peepers at lenstips and photozone panned the teleconverter, but every other reviewer and users rave about it's performance. I admit that I am in the second category, and despite lack of experience with the combo I am very pleased with the performance. It is still very much better than cropping to the same image size (w/40-150) via post so if the 2x performs similar I'd be happy.
     
    • Agree Agree x 4
  8. Giiba

    Giiba Something to someone somewhere

    273
    Aug 19, 2016
    Burnaby, BC
    I think it certain it'll only be compatible with the 40-150 and 300. The 12-100 has a rear element to close to be compatible so that's not going to matter.
     
    • Informative Informative x 1
  9. ijm5012

    ijm5012 Mu-43 Hall of Famer

    Oct 2, 2013
    Pittsburgh, PA
    Ian
    That's assuming that the MC-20 uses a design like the MC-14, where the elements protrude beyond the mounting plane of the converter. If that's true, then yes it won't work with any les but those two. However if Olympus designed it like the EC-series of teleconverters for 4/3 where all of the elements were housed between the two mounting planes, then in theory it would work with any lens.

    Until we see the design, we won't know, but it's reasonable to assume that the design will be similar to the MC-14, in which case it'll only work on a very limited number of lenses.
     
  10. Hypilein

    Hypilein Mu-43 Veteran

    286
    Mar 18, 2015
    I'm assuming the same, but really wish for a different design.
     
  11. Phocal

    Phocal Mu-43 Hall of Famer

    Jan 3, 2014
    There is not a µ4/3 lens I would even consider using this on. Maybe this means they will kick out some remakes of the SHG ƒ2.0 lenses like a 35-100 or a new and improved 150mm ƒ2.0 :biggrin:

    Honestly, my little tuna is the only lens I have found that produces great images with a 2x TC.
     
    • Agree Agree x 2
  12. barry13

    barry13 Super Moderator; Photon Wrangler

    Mar 7, 2014
    Southern California
    Barry


    Supposedly it's due to the very short flange distance on Mu-43.
     
    • Informative Informative x 1
  13. Giiba

    Giiba Something to someone somewhere

    273
    Aug 19, 2016
    Burnaby, BC
    Apparently the patent has been updated with a 1.7x version too. See original link.
     
  14. nstelemark

    nstelemark Mu-43 Hall of Famer

    May 28, 2013
    Halifax, Nova Scotia Canada
    Larry
    Yes this is my experience as well.
     
  15. alex g

    alex g Mu-43 Top Veteran

    542
    Mar 30, 2016
    New York / Bath
    I'm looking forward to the "detonation velocity AF"... :D
     
  16. Giiba

    Giiba Something to someone somewhere

    273
    Aug 19, 2016
    Burnaby, BC
    :hide:
    Sounds dangerous, them crazy Olympus folk are going to hurt someone.